The treatment of persistent pain - Australian Pain Society

� potential death of inhibitory neurons due to excessive release
of nitrous oxide, with associated interference with inhibitory
neuro-transmitters such as GABA;
� genetic changes associated with long term increase response
of neurons; neuroanatomical reorganisation at a brain level,
resulting in increased central representation of"painful areas".
Clinically detectable abnormalities associated with persisting pain can
sometimes be difficult to document. On the other hand, patients with
syndromes such as complex regional pain syndrome (CRPS) can
manifest striking changes including secondary hyperalgesia, allodynia,
hyperpathia, vasomotor changes, abnormalities in motor function
and trophic changes. It is possible that such clinical abnormalities
may be directly linked to the pathophysiology, which has been
identified in animal models, however, such a linkage has yet to be
made. An exciting opportunity to link abnormalities identified at a
basic level with clinical abnormalities may lie in the use of magnetic
resonance spectroscopy (MRS). Philip Siddall and Annie Woodhouse,
in collaboration with Professor Carolyn Mountford, have developed
capabilities to detect regional abnormalities in brain function which
seem to show specific patterns for different pain states.
Perhaps the strongest evidence currently available is from the clinical
psychology literature where a substantial number of abnormalities
have been documented in patients with persisting pain including;
high levels of anxiety, depression, feelings of hopelessness and
helplessness, fear avoidance behaviour, etc. Currently the only factors
that have been identified as being important in the progression from
an acute to a persistent phase are in the psychological domain, and
the only available studies relate to patients with low back pain. It
would thus seem important to study patients following surgery and
trauma to examine whether psychological factors may also be
important in these areas.
Despite the shortcomings in some of the currently available evidence,
there is increasing evidence from the basic and clinical sciences that
persisting pain does become a disease entity regardless of the
underlying causes of the pain. Clearly, the primary objective is to
treat any underlying causes. However, there is also a concern now
that such treatment of underlying causes should be carried out
expeditiously. Otherwise the processes associated with persisting pain
may move into a persistent phase, such that treatment of the
underlying condition may no longer result in a reversal of the pain
process.
6
This month, the physio spot is introducing
(not that they need introduction!)
Tina Souvlis and Bill Vincenzino
Tina and Bill are doing research at the Department of Physiotherapy,
University of Queensland, in the area of central analgesic and motor
effects associated with manual therapy. Obviously, this is an important
area for anyone doing manual therapy – the more we understand
about why and how these techniques work, the more we promote
targeted and effective intervention.
Comments invited: l.moseley@mailbox.uq.edu.au
Manual therapy and pain relief
What reasons spring to mind about the effectiveness of manual
therapy? To most people the thought of "putting something back
into place" or "getting things moving" ie the biomechanical effects
are paramount. However, musculoskeletal pain is one of the main
reasons for attendance at physiotherapy clinics. Physiotherapists
along with other medical and health practitioners have long used
manual therapy techniques in the relief of pain. These techniques
include both manipulation such as a high velocity thrust techniques,
passive oscillatory mobilisation and more recently mobilisation
techniques incorporating active movement.
Manual therapy has long been known anecdotally to be effective
in the management of pain and the treatment of musculoskeletal
conditions. In addition, meta-analyses carried out looking at spinal
manual therapy in the management of both cervical and lumbar spine
pain conditions have demonstrated positive short-term effects.
Although, there is a growing body of literature into the biomechanical
effects of manual therapy until relatively recently there has been little
research carried out into other potential neurophysiological mechanisms
by which these types of treatments may exert some of their effects.
The potential for spinal manual therapy to activate endogenous pain
reliving mechanisms was hypothesized by Wright (1995). Since then,
a number of studies have demonstrated that spinal and peripheral
manual therapy can produce analgesia which is significantly greater
than that produced by placebo or control techniques in a range of
conditions. The hypoalgesia produced by these treatments have
consistently been shown to be specific to mechanical pain thresholds.
Manual therapy treatments do not change thresholds to thermal
pain. This change in mechanical threshold is immediate in onset, it is
not reversible by naloxone and does not demonstrate tolerance to